Re: (userspace) vfs and xio [CAPS?]

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

:This brings me back to wondering about CAPS and it's 128K single message limits.
:
:Is it expected that the user of CAPS would manually break his/her messages into
:<= 128K chunks and then send?  
:
:
:
:> 
:>     But because cross-address-space access are so expensive, it will
:>     probably be more efficient to break a large UIO into an XIO loop
:>     and take the thread switching hit in the loop rather then to try to pull
:>     out a portion of a foreign address space.  Besides, physical I/O
:>     is already limited to 128KB/256KB chunks so the extra thread switches
:>     will not be that big an issue.
:> 
:
:Well yeah... like that for CAPS too?  Or will CAPS include this loop in it's
:implementation?
:
:Seems like a concern that CAPS users shouldn't have to deal with unless it's
:terrbly inefficient to implement the loop in CAPS.
:
:Dave

    I agree completely.  That limit is temporary... it was the easiest way
    to rip out the old cross-address-space junk and use XIO instead.  The
    code needs another pass to add the transfer loop (which is really just
    another one or two states for the message).

					-Matt
					Matthew Dillon 
					<dillon@xxxxxxxxxxxxx>